The subject matter disclosed herein relates to a strain gage and in particular to a multidimensional strain gage.
Use of strain gages is a well-established means of measuring strains on surfaces. They are used by fixing or bonding a strain gage to an article, and using the strain gage as one or more legs in a Wheatstone Bridge or equivalent circuit. As stresses on the article cause it to distort or change its physical shape, the attached strain gage changes its physical dimensions and its resistance to electrical current. The bridge circuit permits the sensitive measurement of this change in resistance. The strain gage correlates the change in resistance to strains in the surface. These prior art strain gages are often made of metal foils, but may also be made from other materials such as semiconductor materials like silicon, which offers a superior gage-factor: a ratio of resistance change to strain applied.
While stain gages may be used to determine dimensional changes in a part, their size has limited this application to dimensional changes over relatively large areas and often unidirectional changes in strain per gage. Accordingly, while existing strain gages are suitable for their intended purposes the need for improvement remains, particularly in providing a relatively small sensor that may be used to determine multidirectional variations across an entire surface.